As a powder metal cladding nozzle, a powder metal cladding nozzle using a laser, shown in FIG. 19, is known (refer to Published Japanese Translation of PCT application, JP-T-10-501463).
A powder metal cladding nozzle 100 shown in FIG. 19 is formed by screwing a rear unit 102 into a front unit 101. The rear unit 102 has a beam passage 103 which extends backward (i.e., upward in FIG. 19) from the front unit 101, and the front unit 101 has an opening 104 at the end of the beam passage 103 such that the axis of the beam passage 103 agrees with the center of the opening 104. A cone-shaped passage 107 is formed between an outer surface 105 of the rear unit 102 fitted in the front unit 101 and an inner surface 106 of the front unit 101. A powder metal supply passage 108 opens into an upper portion of the cone-shaped passage 107.
In the thus formed powder metal cladding nozzle, powder metal is supplied from the supply passage 108 to the passage 107, and the supplied powder metal moves along the passage 107 and is discharged to a process portion W from the opening 104. Also, a beam generated by a laser generator 109 is converged by an optical system 110 such as a lens. The converged beam passes through the beam passage 103, and is irradiated to the process portion W from the opening 104. The laser beam melts the discharged powder metal. A cladding layer can be thus formed on the process portion by using the powder metal cladding nozzle shown in FIG. 19.
With the above-mentioned powder metal cladding nozzle, a good cladding layer can be obtained when cladding is performed while the axis of the nozzle is maintained in the vertical direction. However, when the nozzle is used while the axis of the nozzle is tilted with respect to the vertical direction, the volume of powder metal on the lower side and the volume of powder metal on the upper side become unbalanced in the passage 107 of the nozzle 100 due to gravity. Accordingly, the powder metal cannot be discharged uniformly from the opening 104, which causes a problem that a good cladding layer cannot be obtained.